Method of and apparatus for making metallic walls



Sept. 2, 1924. 1,506,966

F. K. BEZZENBERGER METHOD OF AND APPARATUS FOR MAKING METALLIC WALLS 5 Sheets-Sheet 1 Filed April 17; 1924 INVENTOR. Fred K.Be33enberger Fig.1.

Sept. 2, 1924. 1,506,966

F. K. BEZZENBERGER METHOD OF AND APPARATUS FOR MAKING METALLIC WALLS 5 Sheets-Sheet 2 Filed April 17 1924 INVENTOR. Fred K. Beggenberger EEY Sept. 2, 1924. 1,506,966

F. K. BEZZENBERGER METHOD OF AND APPARATUS FOR MAKING METALLIC WALLS Filed April 1"]. 1924 s Sheets-Sheet 5 Fig.3.

\ l INVENTOR.

1 Fred K. Beggenberger 1,506,966 F. K. .BEZZENBERGER I METHOD OF AND APPARATUS FOR MAKING METALLIC WALLS Sept; 2, x924.

Filed April 17 1924 SSheets-Sheet 4 IN VEN TOR.

Fred K. Bersermberger at VEYJ.

A TT

Sept. 2, 1924. 1,506,966

F. K. BEZZENBERGER I METHOD OF AND APPARATUS FOR MAKING METALLIC WALLS Filed April yr, 1924 s Sheets-Sheet 5 l 1 INVENTOR. 8 a "is V Fred Kfieuenberger Q h AtZ/EEYS.

Patented Sept. 2, 1924.

UNITED "STA TEs PATENT OFFICE.-

METHOD OF AND APPARATUS FOR MAKING METALLIC WALLS.

Application med April 17, 1924. Serial a... 707,205.

To all whom it may concern:

Be it known that I, FRED K. BEZZEN- BERGER, a citizen of the United States, and a resident of Cleveland Heights, county of Cuyahoga, and State of Ohio, have in vented a new and useful Improvement in Method of and Apparatus for Making Metallic Walls, of which the following is a specification, the principle of the invention being herein explained, and the best mode in which I have contemplated apply-.

ing that principle, so as to distinguish it from other inventions. v

The present invention, relating, as indicated, to a method of and apparatus for making metallic walls, is more particularly directed to an improved method of corrugating tubular metallic walls to produce expansible and collapsible hellows for various uses. One of the principal objects of the invention is the provision of a method for corruga'ting bellows'by a fluid pressure which may be very rapidly and economi-.

cally performed, and which will leave the metal of the corrugations produced in the tubular body of a uniformly graded temper. A further object of the invention is the provision of apparatus for carrying out the in which the above method, which may be rapidly and easily operated, and which is practically automatic in its operation, so that the product is uniform in character. 7 To the accomplishm'ent of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain means and one mode of carrying out the invention, such disclosed means and mode illustrating, however, but one of various ways principle of the invention may be used. v

In said annexed drawings:

Figure 1 is a front elevation partially in section of my improved apparatus; Fig. 2 is a side elevation partially in section of the apparatus; Fig. 3 is a horizontal section on the line 3-3, Fig. 1; Fig. 4 is a similar section on the line 44, Fig. 1; Fig. 5 is a section on the line 55, Fig. 1;

Fig. 6 is a section on the line 66, Fig. 1;

Fig. 7 is a side elevation more or less diagrammatic in character showin the controlling meansfor operatin t e apparatus; Fig. 8 is a vertical section through a portion of the die and tubular wall after the first stage of expansion of the wall; Fig. 9 is a similar view showing the wall after it has been completely corrugated; Fig. 10 is an enlarged vertical section through a finished corrugated tube showing the varying thickness therein; Fig. 11 is a section: showing the engagement of the ring and operating means therefor; Fig. 12 is a diagrammatic view illustrating the ratio between the original spacing of the dies and the radius of convolution of the -bellows produced therein; and Fig. 13 is a similar diagrammatic view illustrating the various changes in form of a section of the Wall between the points engaged by the dies during the expanding operation.

The general construction of my apparatus can best be seen in Fig. 1', in which there is shown a base 1, upon which are mounted a series of parallel vertical supports 2 connected by means of an upper plate 4. Fixed centrally to the base member 1 is a cylinder 5, which is open at its upper end, and in which there is reciprocably mounted a piston 6. The upper end of this piston is engaged against a plate 7, which is formed in two halves, each of which is supported at its inner portion on the upper end of the piston 6, and at its outer portion upon ball bearings 8 which roll on supporting platforms 9 and 10, each of which is fixed to the supports 2. Fluid pressure may be admitted below the piston 6 through a conduit 11, see Figs. 1 and 7- The two plates 4 and 7 are each a part of the framework, each plate being connect- .means of links 15 and 16 and a bell cra lever 17, ,which are shownin Fig. 3. The frame is shown in its closed position in Figs. 3 and 4.

Mounted betweenthe plates 7 and 13 are a series of spacing rings 'ZO, which are shown in their initial position in Fig. 1, and which are maintained in spaced relation by means of extensions 71 which engage in spiral cam grooves 18 formed in two drums 19, which are rotatably mounted and 'fixed to shafts 20 which are journaled in the upper plate 13'and the lower late 7, and which extend through and be ow the lower plate. The spacing rings 7 are slidspectively in the upper plates 13 and the lower plate 24. The forming rings 70 and the die head 23 are all semi-circular and open when the two halves of the plates 7 and 13 are swung away from each other and are closed when these plates are swung together and in the relation shown in Figs. 1, 3 and 4.

The piston 6 is hollow, and mounted with in this piston is a second piston 25 which engages the die base 24 and acts to move this base vertically upward upon actuation of the piston 25. Fluid pressure may be admitted to the interior of the piston 6 below the piston 25 through a conduit 26, a slot 27 in the wall of the cylinder 5 and a port (not shown) in the wall of the cylinder 6. The piston 6 has only a limited movement, and the slot 27 is of suflicient length to maintain connection between the port in the cylinder wall 6 and the conduit 26 in all positions of the piston 6.

The piston 25 is provided with a rack member 28 which is exposed through slots formed in the members 5 and 6 (see Fig.5), this rack engaging a gear 29 on a horizontal transverse shaft 30. This shaft 30 is mounted in a fixed position and is connected by meansof double universal joints 31 and 32 on the shafts 33, upon which are carried gears 34engaging with gears 35 mounted on the lower ends of the shafts 20. The shafts 20 are, of course, moved with the plates 7 when the latter are opened, but will remain in mesh with the gears 34 by reason of the movement allowed the shafts 33 through the universal connection with the driving shaft 30. Mounted in the upper plate 4 is a sealing member 7 5 provided with a tapered end 36 adapted to fit snugly within a correspondingly tapered opening in the die head 23. Extending through the member 75 is a relief passage 37 connected to a relief valve 38, which is shown in Fig. 6. The relief valve 38 has a chamber 39 which communicates to the atmosphere through passage 40,

chamber 41 and port 42, the passage being normally closed by means of a springloaded valve 43. The spring is loaded by means of a sleeve sliding over the stem of the valve 43 and having a flange engaging the end of the sleeve. this sleeve then being reciprocably mounted in a removable plug 44 secured in the end of the valve casing 45. At its outer end this sleeve carries a cam follower 46 which is engaged by a cam 47 -mounted on an extension of the shaft 20 in the right cam drum 19. In this way the cam is operated in synchronism with the op eration of the cam drum and the relief valve is opened during the rotation of the tively to the fixed cylinder 5, and to the outer piston 6. There is also shown a con duit 50 leading to the opening in the die head for admitting fluid pressure to the in: terior of the tube which is to be corrugated. In the conduit 50 is a valve 51, which may be used either for closing this line ofi' entirely or for graduating the pressure flowing through the line, and an operating valve 52 for admitting fluid pressure to this conduit from the mam supply conduit 53, to which all of the conduits 11, 26 and 50 are connected. In the conduit 26 is a graduating needle valve' 56, of the same type as the valve 51, and a by-pass conduit 57, in which there is a check valve 59 for allowing a rapid reverse flow, this check valve closing against the direct flow into the piston. There is also in the line 26 an operating valve 60 and a simi- 'lar valve 61 in the line 11.

I corrugate metallic tubes in the following manner. In their initial condition the pistons 6 and 25 are both in their'lowered positions and the die head 23 is below and out of contact with the plug 75. The two dies or plates are open. A tube is now inserted between the forming rings and is rested upon the bottom plate or die 24. Its upper end is first introduced between the adjacent but spaced beveled surfaces 36 on the die head and plug. The die is now closed by operating the bell crank lever 17 The valve 61, is thenopened and fluid pressure is introduced below the piston 6, forcing this piston upwardly and engaging the die head- 23 against the plug with the upper end of the tube clamped therebetween and sealed pressure allowed to increase until the wall of the tube is given an initial set, which is shown in Fig. 8. That is, the metal of the tube wall is bulged out at the points 62 be tween the inner beveled edges 63 of the spacing rings 70. During the initial setting op eration the spacing rings are maintained against movement and the metal in the tube wall is drawn and a temper is induced in each of the bulges. The amount of temper will varybetween the points of the tube which lie against the rings to the center of the bulges. the greatest temper being induced at the point of maximum stretch of metal which is at the plane that is equidistant between the rings 70.

The second stage of the operation is efing actions, are taking p ace: First, the pres-- sure inside of the tube is maintained at initial pressure and is then allowed to remain constant through the operation of the relief valve 38. Second, the spacing rin s are being brought closer together, althoug their equidistant relation is still being maintained, this action being effected by the rotation of the cam drums through the gearing on the rack from the piston 25. Third, the piston is rising and is collapsing the tube in exact time with the decrease in the s acing of the rings, and in time also with the relief of the fluid pressure inside of the tube. When the rings have been brought into contact, as shown in Fi 9,

the form of the corrugated wall is as t ere shown, the tube havmg been forced outwardly into corrugations 66, which are in contact with the beveled faces 67 on the spacin rings 70. The base 24 is formed with alaeveled surface 68, which corresponds to one-half of acorrugation, and this member 24 is of course moved upwardly, but maintained with the same spacing from the next adjacent ring as the spacing between any two adjacent rin during the portion of the o eration. Vl ien the operation is complete the fluid pressure within the cylinder is pumped back to a reservoir, as is also the pressure below the pistons 25 and 6. The die may then be opened and the of the method described, b

corrugated tube or bellows removed. The

operation may then be repeated.

I have found that not only the success ut a so, the sha e and depth of the corrugations, and t e resilient character of the bellows, is dependent, other conditions bein equal, on the ratio between. the distance etween the inwardly projecting crests of the forming rings at the beginning of the operation 100[(AC+ 1.14 B) (1r(C+A))1rCL in which v A=the radius of the outside of the bellows in question,

B=the radius of the bends and is the same for both inner and outer bends, H

C =the radius of the tube,

L=the point-to-point initial setting of the riligs of the die.

f the known values, determined from my tion, I find that area, is 14%; Assuming 14% allowing myself from 5% (which I will call the initial point-to- 1 point setting), and at the end of the opera- I tion, (which I will call the final point-topoint setting). The stretches involved in the operation described are two, and vary in their relation to each other as the diameter of the bellows being formed changes.

First in importance is the stretch due to C the increase in diameter from the tube diameter to the bellows diameter. This stretch, which I will call the circumferential stretch, obvious decreases, for a tion length of one corrugation and the point-to-point initial setting. In most cases this value is negative, that is, the initial settin is of such magnitude that the length of tu e allowed for the formation of one convolution is greater than the cross-sectional lineal length of the corrugation. This is made necessary by the high volume usually maintaining in the small size bellows, for the circumferential stretch. The reduction of the longitudinal stretch to a negative value allows sufficient metal .to flow and compensate for these high circumferential stretches, which would otherwise burst the tube. inches outside diameter this value becomes positive, and with larger sizes, the value increases to compensate for the decrease in circumferential stretch while inducing in the metal suflicient cold work to efiect'suitably resiliency in the product.

Because of the complex character of the =per cent increase in area per convolution.

be substituted in the equathe reduction in thickness of the metal, due to its total increase in reduction de: termined in this Way to be good practice and present practice,

tion I may desire to produce, I have calculated from this equation the data necessary to 25% for varia mg corrugation. Under final setting lies between 2.25 and 10.0.

The metal in the corrugations made by my improved method is graduated in its temper from the crest of the inwardly extending corrugation to that of the outwardly extendthe following conditions, which I have found to give a very satisfactory product,

Material of tube, 80-20 brass,

Thickness of tube, .0075".

Initial spacing of rings, .750".

Final spacing of rings, .250".

Average pressure during forming, 350 lbs. I produce a convolution inch deep, the inner extending corrugation of which has a temper equivalent to thatresulting from a 10% reduction, and the outer extending corrugation has a temper equivalent to that resulting from about 20% reduction. Between these two points the temper varies as evenly as can be determined microscopically.

It will be clear that all of the work necessary to induce convolutions in a straight tube is performed, by my process, without annealing, whereas, in present practice, approximately one-fifth of the actual reduction occurs after the last anneal and is therefore effective in inducing, resiliency. This lim-" itation on the amount of cold working-which can be given these bellows by rolling lies in the localization of the effect of its rolls, whereas, with my process, the effect is more evenly distributed throughout the whole convolution.

In Fig. 13 I have shown a sectlon 85 of the tube wall in its original condition, which is then expanded outward through the various forms shown at 86, 87, 88, 89 and 90 to the finished corrugation. The initial expansion produces a fairly regular expansion and hence drawing or stretching of the metal throughout the longitudinal distance between the initial condition of the two adjacent rings. When the section 86 is further expanded into the form 87 the central portion of this section is increased in diameter and is hence stretched or worked more than. the upper and lower portions of this section of the wallfthe portion which is additionally stretched being included between the lines shown on these figures. The same action is true when the section 87 is expanded into the section 88, and is also true when this section is expanded into that shown at 89 and at 90, so that a gradual increase in the stretching metal is produced, WhlCll. is a minimum at "the bends of the inner corrugations and is a maximum at the bends at the outer corruga- Ftions and varies substantially uniformly therebetween.

Since the radial planes are subjected to stretch and compression it is obviously adyantageous tohave them tempered.

or working of the- Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as .regards the means and the steps herein disclosed, provided those stated by any one of the following claims or their equivalents be employed.

I therefore particularly point out and distinctl claim as my invention 1. ll n a method of making corrugated hollow metallic walls, the steps which consist in mounting a tubular wall within a series of spaced forming rings, inducing an initial pressure within said wall sufficient to expand the same outwardly between said rings and thereby establishing a uniformly graded temper in the metal of such expanded portion, increasing from the point of contact of said wall with said rings to the point of maximum expansion of the portion of said wall between said. rings, and then further expanding the portions'of said wall between" sively collapsing said rings w-hile maintain ing the same in equidistant relation.

3. In.- apparatus of the character described, the combination of a partible die including two series of co-operating partible forming rings adapted to encircle a tube, synchronizing controlling means engaging each of such two series of rings, said means being adapted to progressively collapse said rings while maintaining the same in equidistant relation.

4. In apparatus of the character described, the combination ofa partible die including two series of co-operating par'tible forming rings, each of said series of rings being provided with extending portions, two cam drums provided with a series of-spiral surfaces, each engaging one of said rlngs, and means for simultaneously operating said cam drums to progressively collapse said rings while maintaining the same' in equidistant relation.

5. In apparatus of the character described,

. the combination'of a partible die including rings and normally maintaining the same in equidistantly spaced relation, said means being positive y interconnected with said 'movable plunger and operated to progressively collapse said rings during longitudinal movement of said plunger.

6. In apparatus of the character described, the combination of a partible die including two series of partible spaced forming rings and a partible frusto-conical die head, and means for sealing against the inner surface of said head of the open end of a tube distantly spaced relation, other means for pro.-

gressive y collapsing said rings while maintaining the same in equidistant relation, said rings and means being adapted to maintain a ratio between the initial spacing of the contacting points between said rings and the final distance between contacting points on said rings greater than 2 4 to 1.

9. In apparatus of the character described, the combination of a partible die including a series of partible rings, means normally maintaining said rings in equidistantly spaced relation, other means for progressively collapsing said rings while maintaining the same in equidistant relation, said rings and means being adapted to maintain a ratio between the initial spacing of the contacting points between said rings and the final spacing between the same contacting points on said rings no greater than 10 to 1.

10. In apparatus of the character described, the combination of a partible die including two series of co-operating forming rings adapted to encircle a tube,'and means positively engaging and controlling the spacin of said rings, said means maintaining sald rin s in predetermined spaced relation during t e parting of said die.

11. In apparatus of the character described, the combination of a partible die including two series of co-operating forming rings adapted to'encircle a tube, and means positively engaging and controlling the spacing of said rings, said means reventing relative movement of said rings uring the parting of said die.

12. In a method of making corrugated hollow metallic walls, the steps which consist in radially expanding a tube wall between spaced dies into corrugations while simultaneously axially collapsing such tube during such radial expanding operation a distance sufficient to more than compensate in the final length of the tube wall measured along an elemental longitudinal line for the increase in length produced by such radial expansion.

13. In a method of making corrugated hollow metallic walls, the steps which consist in radially expanding a tubular wall be: tween a plurality of spaced dies into corrugations and collapsing each two adjacent dies axially of said tube a distance such that the initial axial distance between the points of contact of said dies with said tube wall is not less than two' and one-quarter times the final distance, while simultaneously collapsing said tube axially sufliciently to contract its total length measured along an elemental surface line. i

14. In a method of making a metallic bellows from a tube in a single continuous operation the steps which consist in disposing a tube concentrically within spaced axially collapsible rings, expanding the wall of said tube radially outwardly by internal pressure into bulges engaging said rings therebetween, and then simultaneously expanding the wall of said tube further outwardly between said rings while collapsing said rings and the corrugations being formed in said tube wall.

15. In a method of making a metallic bellows from a tube in a single continuous operation, the steps which consist in disposing a tube concentrically within spaced axially collapsible rings, applying an internal hydraulic pressure within said tube and expanding the wall thereof outwardly between said dies sufliciently to produce shallow corrugations engaging said dies therebetween, and then simultaneously expanding the wall of saidtube outwardly between said rings while collapsing said rings and the corruga-t tions being formedin said tube wall.

16. In apparatus of the character described, the combination of a plurality of split axially movable forming rings adapted to encircle a tube, and meansposltively engaging said rings on either side of the split therein, said means acting to simultaneously axially move said rings in either direction.

17 In apparatus of the character described, the combination of a plurality of split axially movable forming rings adapted to encircle a tube, separate means engagin said rings on opposite sides of the same, an other means causing said first-named means to axially move said rings in unison.

18. In apparatus of the character described, the combination of a partible die, including a series of partible rings adapted to receive a tube within the same, a movable base member mounted to move axially with in said partible rings to collapse the tube disposed therein, means adapted to collapse said rings while maintaining the same in equidistant relation, and meansnsynchronip' ing the movement of said base and said rings.

19. In apparatus of the character described, the combination of a partible die,

including a series of partible rings adapted to receive a tube within the same, means adapted to exert fluid pressure within said I movement of said base member, said means 7 engaging and collapsing said rings.

Signed by me, this 8th day of April, 1924.

' FRED K. BEZZENBERGER. 

